docs: def push_docs(deploy_branch='gh-pages', retries=5):
      """
      Push the changes to the branch named ``deploy_branch``.
  
      Assumes that :func:`setup_GitHub_push` has been run and returned True, and
      that :func:`commit_docs` has been run. Does not push anything if no changes
      were made.
  
      """
  
      code = 1
      while code and retries:
          print("Pulling")
          code = run(['git', 'pull', '-s', 'recursive', '-X', 'ours',
              'doctr_remote', deploy_branch], exit=False)
          print("Pushing commit")
          code = run(['git', 'push', '-q', 'doctr_remote',
              '{}:{}'.format(DOCTR_WORKING_BRANCH, deploy_branch)], exit=False)
          if code:
              retries -= 1
              print("Push failed, retrying")
              time.sleep(1)
          else:
              return
      sys.exit("Giving up...")